Mold for casting steel



{Ne M0d 1 2 Sheets-Sheet 1.

J. HENDERSON. MOLD FOR cAsTING STEEL.

No. 315,741. a I a, 1% egl Apr. 14, 1885.

. it P v WITNESSES.

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2 Sheets-Sheet 2.

(No Model.)

J. HENDERSON.

. V MOLD FOR CASTING STEEL. No. 315,741.

Patented Apr. 14, 1885.

a ly 12 UNITED STATES PATENT OFFicE,

JAMES HENDERSON, OF BELLEFONTE, PENNSYLVANIA.

MOLD FOR CASTING STEEL.

SPECIFICATION i'orming part of Letters Patent No.315,741, dated April14, 1885.

Application filed March 3, 1885. (No model.)

To (LZZ whom it may concern:

Be it known that I, JAMEs HENDERSON, formerly of the city, county, andState of New York, now of Bellefonte, in the county of Gentre and Stateof Pennsylvania, have made an invention of certain new and usefulImprovements in Molds for Casting Steel and other Fluid Materials; and Ido hereby declare that the following, in connection with theaccompanying drawings, is a full, clear, and exact description andspecification of the same.

This invention has reference to the compression or condensation of steeland other materials in molds, and the expulsion of gaseous matter fromthe material by gaseous pressure; and the invention consists of certaincombinations of devices, which are recited in detail in the claims atthe close of this specification. fully understood, I have represented inthe accompanying drawings, and will proceed to describe, the best modewhich I have thus far devised of embodying the invention for practicaluse when a cylindrical article-such as an ingot for a steel cannonis tobe cast.

The drawings represent at Figure 1 a cen tral longitudinal section ofthe mold and its appurtenances for the cannon-ingot. Fig. 2

is a vertical section, on a larger scale, of the cover of the mold, withan inverted cup and powder-chamber secured to it. Fig. 3 is a section ofthe inverted cup before its application to the cover of the mold.

The mold for the cannon-ingot, as represented in the drawings, isformed, mainly, in a flask, M, whose walls are perforated by orifices z,for the escape of gas, the body of the flask being constructed ofsections connected by flanges G and bolts 0, in the usual manner. Theflask is closed at its lower end by the bottom plate, I). The interiorof the mold in the flask is made, in the usual manner, of damp sand, 13,rammed around a pattern, which, for convenience of being drawn from themold, should be made in sections, held in their proper rela tivepositions to each other by means of pins, as well understood in the artof molding for castings. When the mold has been formed,

the sections of the flask are separated, the pat tern is drawn out, andthe sand lining of the In order that the same may beflask is thoroughlydried before the sections are put together to be poured with the fluidmetal.

The head M of the mold is formed, by preference, of cast-steel, which isconnected with the sand-lined flask beneath by means of flanges andbolts; and the joint between the head and flask is made tight,preferably by means of a gasket of copper, which is applied tocorresponding grooves, 1 formed in the adjacent rims of the flask andhead, which should be faced off truly to make a close joint. The gasketmay have a circular section before it is applied to the grooves, so thatwhen the head of the mold is drawn down to the upper end of the flask bythe bolts the gasket will be compressed, and will close the jointhermetically. The upper end of the head of the mold has a cover, P,fitted to it, and the joint between the cover and the head of the moldshould be made gas-tight by some suitable means-such, for example, as agasket, I, of soft metal, or an inverted cup of thin sheet metal,secured to the cover, which cup may be expanded by the pressure of gasgenerated within the mold. This invention. however, is not restricted toany particular means for making the joint gas'tight. The gaseouspressure for compressing the material in the mold is generated withinthe mold after its head is closed, and preferably by the burning of apowder composed of eighty parts, by weight, of saltpeter and twentyparts of charcoal, which may be used in quantities of about one hundredand forty-seven grains for each cubic inch of space left in the head ofthe mold between its cover and the surface of the cast metal, and themold must be strong enough to withstand this pressure. I estimate thatthis quantity of the said gas material will produce a pressure upon thecast metal of about eight tons to the square inch. For the purpose ofholding this gas material a chamber, II, is secured to the under side ofthe cover P. This chamber is closed by a bottom which is fitted tightlyin the wall of the chamber, but is not fastened thereto. In order thatthe gas material may be ejected from the chamber, a plunger, 0, isfitted in the cover 1?, with the rod of the plunger extended through ahole in the cover and fitted at its upper end with a knob, a, which maybe struck by a hammer, and for the purpose of limiting the downwardmovement of the plunger a collar is secured to the plunger-r0 In orderto facilitate the displacement of the bottom of the chamber, a smallwooden plug is introduced into the chamber between its bottom and theplate of thin metal of the inverted cup,which forms the top of thechamber next to the under surface of the cover of the mold.

When the mold is to be poured with fluid steel, it is opened at the topby the removal of the cover. The fluid steel is run into the moldpreferably by means of a pipe of cast-iron inserted in the mold, and themold is nearly filled, say, within six inches of the upper end of thehead. I prefer to use a steel plate, S,

which, previously heated to a red heat, is lowered upon the fluid metal.The cover of the mold with the charge of powder in its chamber isapplied and made fast, after which the charge is discharged from itschamber by a blow upon the knob of the plunger 0. The powder is ignitedby the heat of the plate S, upon which it falls, and as the gasesgenerated by its ignition are confined within a small space a stronggaseous-pressureisproduced,whichcompresses and condenses the steel. Asthe flask portion of the mold is lined with dried sand,which is perviousto gas, the force of this pervious lining permits the escape of the gasfrom the steel which is in the flask portion of the mold when the steelis subjected to the pressure of the gas generated in the head-of themold from I the gas material, while as the head of the mold is ofmetal,which is impervious to gas, it prevents the escape laterally andupward of gas generated by thegas material, and the portion of the fluidmetal in the head above the sand-lined flask prevents the downwardescape of the gas from the gas material, so that it acts with its fullpressure upon the metal in the mold. 7

From the foregoing description it will be perceived that the inventionis characterized by the combination of the body of the mold pervious togas with a head that is impervious to gas, the former permitting theescape of gas from the cast metal, and the latter confining thecompressing-gas generated from the gas material so that thecompressinggas exerts its pressure upon the cast metal.

The invention is not restricted to the use of the above-describedcompound of charcoal and saltpeter as the gas material, as other gasmaterial may be used for the purpose. Thus,

.for example, the gas material may consist of water in the'form of. iceintroduced into the chamberH immediately before the cover P is appliedto the head of the mold.

I prefer to make the pervious lining B of clean sharp sandsuch asfire-sandintimate- 1y mixed with magnesian lime in the proportio'ns ofninety-five parts,by weight, of dry sand to five parts of magnesianlime. is made preferably by slaking the lime and adding sufficient waterto make it of a creamy consistency, and then intimately mixing it withthe sand. I also prefer to paint or wash the inner. surface of the moldwith rye-flour and water. This wash should be thoroughly dried upon themold before the latter is put together to receive the fluid steel.

In place of expelling the gasmaking material from its chamber andigniting itby the heat of the casting, it may be ignited in the chamberby electricity. In this case the electricity is conducted to the gasmaterial, as

represented at Fig. 2, by means of a duplex conductor, a, and the twowires of the con-v ductor are connected by a platinum wire, a", in thecharge of gas material, so that the platinum wire is ignited by theelectricity and fires the. gas material. WVhen an inverted cup is usedfor making the joint of the cover of the mold gas-tight, I prefer toconstruct it, as represented in section at Fig. 3, with a flange, b,which can be compressed in the joint.

In order to prevent accidents which may arise from explosions, it ispreferred to use a cover of thick boiler-plate balanced by a weight andlowered over the entire mold directly after pouring the metal, and afterplacing and securing the cover 1?, this safety-cover being arranged sothat in lowering it it forces the plunger upon the top of the cup andcauses the powder to be discharged upon the metal.

I claim as my invention 1. The combination, substantially as before Themixture set forth, of the flask pervious to gas, the head JAMESHENDERSON.

WVitnesses:

Row. R. BREVOORT, J. E. WVARNER.

